Increased concentrations of some aromatic amines (phenylethanolamine and octopamine) have been reported in plasma and urine of patients in hepatic coma. Some of the symptoms of hepatic coma may be due to accumulation of these amines. These amines could be formed by bacteria in the gastrointestinal tract, absorbed into the circulation and spared from normal metabolism when the liver is not functioning properly. Or they may be produced endogenously from the precursor amino acids which accumulate progressively in plasma and in tissues when liver function is impaired. The hepatectomized rat will be used as an experimental model to study biochemical changes that occur in the absence of normal liver function. A study of the disposition and metabolism of the aromatic amines tyramine, octopamine, phenylethylamine and tryptamine in hepatectomized and in control rats with external bile fistulas is proposed. It is also suggested that the formation in brain of tyramine, octopamine and norepinephrine from tyrosine be studied in hepatectomized and in control rats. Hepatic coma in patients has been treated with considerable success by the administration of L-3, 4-dihydroxyphenylalanine (dopa). It is proposed also to study disposition and metabolism of dopa in hepatectomized and in control rats. BIBLIOGRAPHIC REFERENCES: Tyce, G. M. and Owen, C. A., Jr.: The metabolism of beta-phenylethylamine in normal and in hepatectomized rats. Fed. Proc. 35:308, 1976. Beattey, O., III, Tyce, G. M. and Donald, D. E.: Mechanism of "sympatholysis" in exercising skeletal muscle. The Physiologist 18:134, 1976.